Stefan Nielsen
Library for reading data from the RHT03 / DHT22 digital humidity & temperature sensor.
Dependents: Pachube-v2_DHT22 DHT_TEST2 DHT_CANSAT Projeto_Monit_Remoto ... more
Revision 0:7fd3ff04ae95, committed 2011-10-27
- Comitter:
- Julepalme
- Date:
- Thu Oct 27 15:11:06 2011 +0000
- Commit message:
- First Draft
Changed in this revision
| DHT22.cpp | Show annotated file Show diff for this revision Revisions of this file |
| DHT22.h | Show annotated file Show diff for this revision Revisions of this file |
diff -r 000000000000 -r 7fd3ff04ae95 DHT22.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DHT22.cpp Thu Oct 27 15:11:06 2011 +0000
@@ -0,0 +1,49 @@
+#include "DHT22.h"
+
+
+DHT22::DHT22(PinName pin) {
+ _data_pin = pin;
+}
+
+int DHT22::getTemperature() {
+ return _temperature;
+}
+
+int DHT22::getHumidity() {
+ return _humidity;
+}
+
+bool DHT22::sample() {
+ DigitalInOut DHT22(_data_pin);
+ int dht22_dat [5];
+ DHT22.output();
+ DHT22.write(0);
+ wait_ms(18);
+ DHT22.write(1);
+ DHT22.input();
+ wait_us(40);
+ wait_us(80);
+ int i,j,result=0;
+ for (i=0; i<5; i++) {
+ result=0;
+ for (j=0; j<8; j++) {
+ while (DHT22);
+ while (!DHT22);
+ wait_us(50);
+ int p;
+ p=DHT22;
+ p=p <<(7-j);
+ result=result|p;
+ }
+ dht22_dat[i] = result;
+ }
+ int dht22_check_sum;
+ dht22_check_sum=dht22_dat[0]+dht22_dat[1]+dht22_dat[2]+dht22_dat[3];
+ dht22_check_sum= dht22_check_sum%256;
+ if (dht22_check_sum==dht22_dat[4]) {
+ _humidity=dht22_dat[0]*256+dht22_dat[1];
+ _temperature=dht22_dat[2]*256+dht22_dat[3];
+ return true;
+ }
+ return false;
+}
diff -r 000000000000 -r 7fd3ff04ae95 DHT22.h
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DHT22.h Thu Oct 27 15:11:06 2011 +0000
@@ -0,0 +1,17 @@
+#ifndef MBED_DHT22_H
+#define MBED_DHT22_H
+
+#include "mbed.h"
+
+class DHT22 {
+private:
+ int _temperature,_humidity;
+ PinName _data_pin;
+public:
+ DHT22(PinName);
+ bool sample();
+ int getTemperature();
+ int getHumidity();
+};
+
+#endif
\ No newline at end of file